Container for manufacturing sintered products

ABSTRACT

A container for manufacturing an alkali product by introducing powder into the container and sintering the container under pressure to form a solid body in a pressure furnace where it is subjected to high temperature and all-sided pressure, includes a pair of plates which at their outer parts form a forming space and at their center part form a disc-shaped central portion having a central opening and an annular wrinkle, and a discshaped gap extending between the central opening and the forming space through which powder introduced through the central opening may pass into the forming space under the action of centrifugal force.

United States Patent [191 Danieli et a1.

1 CONTAINER FOR MANUFACTURING SINTERED PRODUCTS [75] Inventors: Stan Henrik Danieli; Arne Sundstrand, both of Vasteras, Sweden [73] Assignee: Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden [22] Filed: Dec. 3, 1973 [2]] Appl. No.1 420,924

[30] Foreign Application Priority Data Dec. 5, 1972 Sweden 15816/72 [52] US. Cl...- 425/78, 425/405 H [51] Int. Cl B30b 5/02, B30b l1/00 [58] Field of Search 425/78, 405 H [56] References Cited UNITED STATES PATENTS 2.298.908 10/1942 Wentworth 425/405 H X [451 Nov. 26, 1974 3,529,321 9/1970 Culand 425/405 H X 3,559,236 2/1971 Merritt 425/405 H X 3,593,382 7/1971 Miller 425/78 Primary ExaminerJ. Howard Flint, Jr.

571 ABSTRACT A container for manufacturing an alkali product by introducing powder into the container and sintering the container under pressure to form a solid body in a pressure furnace where it is subjected to high temperature and all-sided pressure, includes a pair of plates which at their outer parts form a forming space and at their center part form a disc-shaped central portion having a central opening and an annular wrinkle, and a disc-shaped gap extending between the central opening and the forming space through which powder introduced through the central opening may pass into the forming space under the action of centrifugal force'.

3 Claims, 4 Drawing Figures CONTAINER FOR MANUFACTURING SINTERE PRODUCTS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a container intended for use in the manufacture of an annular product, starting from a powder which is introduced into the container and thereafter sintered in the container to form a solid body. The container with the powder is usually first pressed isostatically at room temperature, after which it is heated and inserted into a pressure furnace where it is simultaneously subjected to high temperature and an all-sided high pressure from a pressure medium enclosed in the pressure furnace, usually an inert gas such as argon or helium. The furnace soace itself is enclosed in a pressure chamber which absorbs the pressure medium forces. The container is particularly intended for manufacturing rings of high-speed steel or super-alloys, which are given their final shape by being further machined, for example by forging or machining. Rotor rings for gas turbines can be advantageously manufactured, but also turbine blades or other bodies which are not annular in their finished condition but which consist of a ring with outwardly projecting blade blanks from which blades are machined.

2. The Prior Art Powder with a high, even quality can be manufactured by atomizing a molten alloy in an argon atmosphere. Because of the quick cooling of the metal drops formed, a spherical powder with homogeneous composition and extremely fine grain structure is obtained. It is almost impossible to form a durable, workable body of this spherical powder without the help of a binder. Bodies should therefore be formed by packing powder in moulds which have a cavity corresponding to the desired shape of the powder body.

RELATED APPLICATIONS The centrifugal apparatus is claimed in an application of the same inventors, Ser. No. 420,921, filed Dec. 3, 1973.

SUMMARY OF THE INVENTION The container according to the invention is preferably symmetrical about an axis with an annular forming space and a disc-shaped central portion with two walls between which a disc-shaped gap is formed. In one wall is an opening through which powder is introduced into the container while this is positioned in a centrifugal machine and rotates at high speed. By the rotational forces the powder is transported from the opening through the gap of the central portion to the forming space, where it is compacted and forms an annular powder body. The container and the manner in which it is filled gives a uniform density in the whole powder body, which is a requisite condition if a finished product is to acquire the proper characteristics and the same form as the forming space. The disc-shaped central portion is provided with one or more annular wrinkles. The shape of the central portion is of very great importance. The gap therein should be as small as possible, but should allow the powder being used to flow unimpededly from the opening into the forming space. However, the gap should be so small that it forms a stop which prevents powder from flowing back when the rotation ceases and so small that the amount of powder in the central portion only causes an insignificant loss of material. The wrinkles in the disc-shaped part have two separate, important functions. They increase the locking action and reduce the radial stiffness so that the central portion will only insignificantly prevent the radial shrinking when the dimensions of the powder body are reduced during the pressing and sintering processes. The low radial stiffness reduces the risk that the ring will be distorted during the pressing.

In many cases the container can be constructed from only two plate halves which are welded together at the periphery of the container. The central portion of one or both plate halves may be provided with inward projections which keep the walls of the hub part at the desired distance from each other. At the projections the plates may be welded together, for example by means of spot welds. Also plates may be used as spacers.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPIIONQOF THE PREFERRED EMBODIMENTS In the drawings, 1 designates a container placed inside a centrifugal machine 2. The container is constructed from a lower plate 3 andan upper plate 4 forming a forming space 5. The plates are joined by a seam weld 6 at the periphery. The hub parts 7 and 8 of the plates are provided with wrinkles 9 and l0.- Between the hub parts 7 and 8 is a gap 11, the size of which is determined by the spacing means comprising spaced inward projections 12, which occupy a part only of the space between the plates. The hub parts of the plates are joined by the spot welds 13. At the center of the container is an outwardly threaded sleeve 14 which is joined to the hub part 8 of the plate 4 by a weld 15. As shown in FIG. 3, a plut 16 is inserted into the sleeve 14 when the powder has been filled in. The diameter of the plug is so chosen with respect to that of the sleeve that the seal is gas-tight as the plug is pressed into the sleeve. A weld l7 ensures a permanent gas-tight sealing during heating and pressing. FIG. 3 shows the size after pressing.

The centrifugal machine comprises a rotatable disc 20 with a guide 21 adjusted to the container and fastening members 22 which clasp the peripheral flange 23 of the container. The sleeve 14 is screwed to the central portion 24 of the disc 20. The disc 20 has a tubular central portion 25 which is joumalled in the sleeve 27 by means of bearings 26. Said sleeve 27 is supported by rubber elements 28 and 29 which are attached to a tubular part 30, which is supported by studs 31 in a stand (not shown). A tube 32 joined to the sleeve 27 forms elastic connection sleeve 38 which makes contact with the neck 39 of the receptacle 33 in a sealing manner.

The disc 20 is provided with a flange 40 with a groove for a V-belt 41. The disc is driven by a motor 42 which is attached to the part 30.

The centrifugal machine can be rotated at least 180 around the shaft pins 31. When the receptacle 33 is mounted in the holder, the part of the centrifugal machine shown is turned 180 from the position shown, the disc 20 being positioned at the top and the receptacle holder 32 at the bottom. A receptacle 33 can be mounted from above in the holder, the part 24 with the funnel 35 and the container 1 can be mounted in and on the disc 20, after which the centrifugal machine is turned to the position shown in FIG. 1. When the disc 20 is rotated the powder running down into the sleeve 14 is thrown through the funnel 35 into the forming space 5. An efficient filling of complicated forming spaces is made possible by the fact that, while being rotated, the disc may vibrate and the centrifugal machine may be turned to more or less inclined positions.

We claim:

1. Container for manufacturing an annular product, starting from a powder which is introduced into the container and thereafter sintered in the container under pressure to form a solid body by inserting it into a pressure furnace and therein simultaneously subject it to high temperature and an all-sided pressure from a pressure medium enclosed in the pressure furnace, said container comprising plates which at their outer parts form a forming space and at their central part form a disc-shaped central portion with a central opening and an annular wrinkle and a disc-shaped gap extending between the central opening and the said forming space.

2. Container according to claim I, in which the discshaped central portion contains spacing means which determine the size of the gap.

3. Container according to claim 1, in which the plates are welded together at the spacing means. 

1. Container for manufacturing an annular product, starting from a powder which is introduced into the container and thereafter sintered in the container under pressure to form a solid body by inserting it into a pressure furnace and therein simultaneously subject it to high temperature and an all-sided pressure from a pressure medium enclosed in the pressure furnace, said container comprising plates which at their outer parts form a forming space and at their central part form a disc-shaped central portion with a central opening and an annular wrinkle and a disc-shaped gap extending between the central opening and the said forming space.
 2. Container according to claim 1, in which the disc-shaped central portion contains spacing means which determine the size of the gap.
 3. Container according to claim 1, in which the plates are welded together at the spacing means. 